These last two weeks conclude my summer internship at the Oakland Zoo. During my past three months as an intern, I’ve made popsicles for lemurs, I’ve given belly rubs to pigs, and I’ve befriended a goat. By the end of my summer, I have become familiar with zoo animal husbandry through my daily routine and through the intern classes. The Oakland Zoo’s intern program is an excellent opportunity to gain experience working with zoo animals.

Nubian goats in the Oakland Zoo’s contact yard.

Oftentimes, I work in the Children’s Zoo contact yard, where visitors brush and pet the plethora of sheep and goats. The yard houses five sheep, six Pygmy goats, four Nubian goats and one Boer goat. The Pygmy goats are particularly popular among the zoo’s children visitors because of the goats’ short stature and tolerant attitude. Working in the contact yard involves keeping the area clean while ensuring the safety of the visitors and animals. There is a retreat pen in the barn where goats and sheep can retreat, if they want some personal space from visitors.

Scarlet, one of the three cats, wearing a “Cat Bib” when she goes outside of the cat cottage.

Three long-haired cats named Billy, Cali and Scarlet live in the “cat cottage” adjacent to the Contact Yard. After feeding the goats and sheep in the morning, I usually let the cats outside into the Contact Yard and made sure they didn’t wander off. Whenever the cats roam outside, they wear “cat bibs” that are designed to prevent them from successfully catching birds. The bibs are supposed to inhibit their normal pouncing motion, and I think they’re quite the fashion statement.

As part of the animal husbandry, I brush Ginny with the FURminator before letting her out on exhibit.

Part of my routine is brushing Ginny, one of the rabbits before letting her out of the night house. She was slightly skittish the first time I brushed her, but soon after she relaxed and began munching on her hay. Rabbits shed quite a bit of hair, but the FURminator helped me loosen and remove the undercoat.

On Tuesday, I got the chance to spend a few hours working up at the giraffe barn. I helped fill containers with pellets and produce, while the giraffe intern hung up branches of browse. My absolute favorite moment was hand feeding carrots to Tiki, one of the zoo’s giraffes.

Tiki is one of the Oakland Zoo’s giraffes.

Summer is quickly coming to a close. Shortly, I’ll be back in college fighting sleep deprivation and jumping headfirst into fall quarter classes. In some ways, it seems like I’ve been interning for far more than three months; I can’t imagine not feeding breakfast to the lemurs or hearing the familiar bleating of the goats in the morning.

I scratch the belly of a Guinea Hog lying down on his side while zookeeper Liz trains him to accept a blood draw. The Oakland Zoo’s Veterinary Care Center wants a blood sample to determine if the animals’ new diet has the proper nutrients. To prepare the two Guinea Hogs for an actual blood draw, they first have to become tolerant about a person holding off their leg to find the vein. Due to their excellent sense of smell, Jason and Sara initially were nervous about the rubbing alcohol on their legs. Also, the zookeeper practiced touching their legs with a blunted needle to accustom them to the motions of a blood draw. Some of the zoo’s visitors who saw us practicing in the exhibit appeared surprised that the pigs were so tolerant and even asked if the Guinea Hogs were sedated. Nope, they weren’t. They simply enjoy their belly rubs and are willing to lie down on the grass.

Jason, one of the Guinea Hogs, laying down for belly rubs during a blood draw training session.

The less glamorous aspects of my internship are the routine cleaning and disinfecting of the animals’ exhibits and night houses. I completely gutted and disinfected the rabbits’ night house, and then I filled it would fresh shavings and grass hay. The other intern and I also scrubbed the pools in the pigs’ exhibit along with disinfecting their night house and service area.

Lemur popsicles consist of fruit frozen in cups of water. The popsicles are used as enrichment on warm days.

The past few days have been warm and sunny – the perfect opportunity for making popsicles for the lemurs! A lemur enrichment popsicle consists of fruit chucks (usually grapes, watermelon, strawberries and cantaloupe) frozen in ice.

Besides continuing to conduct lemur observations for an intern project, I attended an intern class about zoological population management. This class concludes the series of intern classes and explained how zoos determine which animals to breed and to whom to breed them. The class covered what is included in a stud book and general population management concepts, like avoidance of inbreeding. I learned the founding populations in a stud book are animals directly from the wild.

For lemur observations, we do a visual scan of the exhibit every two minutes and record the behavior of a certain lemur.

Another guideline was not to keep all animals of one species concentrated in one zoo. In case of an emergency, zoos would not want all the animals of a particular species to die.

Gripping a stopwatch, pen and clipboard in the palms of my hands, I walk up towards the Oakland Zoo‘s lemur deck to conduct observations. Typically directly after serving one of their meals, the other intern and I will pick two lemurs and record their behavior for up to an hour. The behavior categories include interacting with enrichment, which we vary throughout the week. By recording how much time a lemur spends on a particular activity, we can construct a graph of their “typical day.” When I first began interning on String 7, it was difficult to identify and tell apart any of the lemurs. Now, I am able to distinguish the animals apart by their physical characteristics and personality.

Ring tailed lemurs interacting with phone book enrichment item.

“Are the lemurs reading?” one visitor asked me after I served their lunch. No, the phone books were one of the manipulative enrichments used this week. Stuffing pieces of produce between the phone book’s pages encourages the lemurs to manipulate the item to reach the food. By conducting observations of the lemurs, I can later analyze the data and compare the effectiveness of each enrichment item. Even though PVC pipe connectors, cat litter containers, and cardboard boxes sound like an odd combination, they are other examples of manipulative lemur enrichment. Both the plastic cat litter containers and cardboard boxes contain holes into which the lemurs must reach, and we sometimes use clips to hang up two of the plastic containers.

Eugene and Anthony, the two blue-eyed black lemurs, slowly approached me while eyeing the dried cranberries in my hand. I felt the smoothness of Eugene’s palms as he reached out to grasp the cranberry. His aquamarine eyes darted around as he chewed the sliver of cranberry. On Wednesday morning, I got the chance to assist the zoo keeper with cooperative feeding out on exhibit. Cooperative feeding rewards the dominant individual for letting the subordinate individual to eat in its presence. The male ring tail lemur, Jeager, is subordinate to the three female ring tail lemurs; the two blue-eyed black lemurs are also subordinate to the females. Every time the dominant female saw me feed the blue-eyed black lemurs that were about 10 feet away, the zoo keeper would reward her for not chasing them away. Helping with cooperative feeding is an opportunity to work closely with the lemurs and observe how it shapes their behavior.

One of the Oakland Zoo’s vet technicians led this week’s behind-the-scenes tour of the Veterinary Care Center (VCC). I got to see some of the portable equipment the VCC staff uses, such as the anesthesia and x-ray machines. The vet technician showed us the various sizes of tracheal tubes used for anesthetizing the zoo animals, which range in size from a small bird to an elephant. She said that the VCC sometimes will coordinate with other veterinarians for major procedures. For the larger animals, such as elephants and lions, the VCC staff can exam or treat them in their night house because they will not fit into the surgery room.

Wooden feeders are an example of manipulative enrichment.

Plastic cat litter containers have holes cut in the sides. They can be hung up in the exhibit so lemurs must balance and reach inside for food items.

Throughout this week of my internship, I got to both learn more about operant conditioning and participate in training a few zoo animals.

We turn on a misting hose in the guinea hogs' exhibit on warm days.

The week began with walking Jason and Sara, the two Guinea Hogs, up to the Oakland Zoo‘s Veterinary Care Center to weigh them. Three other interns and I worked to harness them and continue the training we started last week. Two of us were in charge of delivering the reinforcement; in this case it was a variety of chopped produce. The other two held the leash, harness and clicker. It was important the rate of reinforcement was not too low or the Guinea Hogs might lose interest and turn to foraging. When training any animal, especially one that is as large and strong as a Guinea Hog, it is imperative to be alert to your animal. For instance, Sara is afraid of large and loud trucks so we remained aware of our surroundings while leaving the Children’s Zoo. In this week’s intern class on operant conditioning, I learned that escape is a primary reinforcer and permanent associations about something can last for years.

Patrick, one of the Nubian goats, in the main stall of the contact yard.

As part of the routine animal husbandry, zoo keeper Alan works with the goats and sheep to trim their hooves. During this week, I got to give out the reinforcement, which was food, to the sheep during the training session. Although the zoo keepers oftentimes use clickers to mark the behavior, Alan whistles instead because he uses both his hands to hold the animal’s leg and to hold the pair of hoof trimmers. The sheep appeared more skittish than the goats about hoof trimming. Alan had them stand on a mat during the training session, and he also worked to desensitize one of the sheep to touching its hind legs in preparation for the actual trimming part.

A ring tail lemur interacting with enrichment. The PVC connector stuffed with food and straw is a form of manipulative enrichment.

As I mentioned in my Week 2 blog post, the lemurs get daily enrichment, which I mark on the calendar. String 7 zoo keeper Liz organized the list of possible enrichment into categories, such as manipulative, environmental or sensory. Manipulative enrichment includes putting food into containers with holes so the lemurs have to manipulate the object to retrieve their meal. One day this week, I helped fill plastic PVC connectors with their lunch and straw. After doing a thorough scrub of the lemurs’ night house in the morning, the other interns and I did a little interior designing. We rearranged the “furniture” inside the night house, which is a form of environmental enrichment.

A ring tail lemur eating a piece of Romaine lettuce, one of the leafy greens in their diet.

A major part of this week included conducting observations of the lemurs. Depending on the type of observations, the time intervals range from every 30 seconds to every 2 minutes. Usually I pick an easily identifiable lemur to observe while another intern keeps track of the time. The categories on the observation sheet comprise of social behaviors, like huddling with another lemur or being groomed, and also of agnostic behaviors like marking with scent glands or chasing. The observations can be done any time of the day and inform the zoo keepers on how the lemurs interact with enrichment and with each other. The data collected can be used to make ethograms or to determine what percentage of the day a particular lemur does a certain activity.

One form of enrichment is scattering their diet throughout the grassy areas of the exhibit. Three of the ring tail lemurs foraging for their food and sunning themselves.

I grip a small plastic box in the palm of my hand. I press down on its metal tab. Click! Immediately, a crisp snapping sound fills the air.

Many zoo keepers use clicker training to shape an animal's behavior.

As part of the Oakland Zoo intern program, we attend weekly classes and behind-the-scenes tours. This week’s class was an “Introduction to Operant Conditioning,” which highlighted how zoo keepers use clicker training to shape animal behavior. The crisp click is a trademark of clicker training, which I learned more about during the intern class.

Much like a college intro to psychology course, the class began by describing experiments done by Pavlov. Pavlov would ring a bell (conditioned stimulus) directly before giving food (unconditioned stimulus) to the dog, which caused the dog to salivate (unconditioned response). Eventually, the dogs would salivate when he rang the bell. We also learned about Throndike’s Law of Effect and how consequences influence how likely a behavior will be repeated. In addition, the class taught us how to distinguish between negative/positive reinforcement and negative/positive punishment. Although using punishment might produce faster results, clicker training is a method of positive reinforcement used to shape an animal’s behavior.

Joseph (left), one of the Nubian goats, participated in this week's intern class demonstration.

To practice the skills learned in the class, we walked out towards the goat and sheep yard to clicker train the goats with zoo keeper Liz. The click, which acts as a marker, is immediately followed by a food treat, which is the reinforcement. This way, the animals know the exact moment for which he or she is being rewarded. Using a technique called “shaping,” Liz worked with us to teach a goat to spin while standing on a short wooden table. First, she would reward the goat for a left head turn and then for a shift in body weight, building up towards a complete spin. Only the domestic animals, like goats, are trained to do tricks; the other zoo animals are only trained to do behaviors that help with animal husbandry tasks or veterinary needs. For example, some of the zoo animals are trained to hold still while getting x-ray, injections or blood drawn.

Photo credit: Lisa Clifton-Bumpass

During this week, three of the other interns and I got the opportunity to work with volunteer Lisa on pig training. After harnessing up the pigs, we practiced commands such as taking a step left, right, forward, backwards or standing still. It was extremely important to mark the behavior with the clicker before moving to drop the food reward. In addition, when feeding the reward, I placed it in a spot that reinforces the behavior. For instance, if I wanted a “back up,” I would not place the food reward so the pig had to take a step forward to eat it.

Zoo keeper Liz training one of the pigs to rest her head on a crate for eye cleaning.

The handler gave each of the commands to the pig through the harness, making sure the commands were clear. Sometimes we would use contrasting commands, like giving a “left step” cue after practicing several “right steps.” Through clicker training, many of the zoo animals do not need to be put under anesthesia or physically restrained for simple procedures, like giving vaccinations, trimming a goat’s hooves or cleaning a pig’s eyes.

Much like Top Chef contestants must complete culinary challenges with certain ingredients, both zoo keepers and Oakland Zoo commissary staff must prepare diets for the animals according to specific requirements. Although Top Chef contestants work under the camera spotlight to please the reality show judges, zoo keepers may appear to work more in the background. However, both work under a time constraint.

On Tuesday afternoons, I work in the zoo commissary to assist in the preparation of diets. This week I began by helping a volunteer prepare the birds’ diets and then started cutting up produce into two inch pieces for the “elephant buckets.” These buckets consisted of two buckets of potatoes, one of apples and one of bananas, totaling about 40 pounds. It’s safe to say that I have never sliced so much produce at one time!

Beginning to prepare the lemurs' breakfast. Part of their breakfast is sweet potatoes and canned primate.

This week, the commissary received a new shipment of live crickets and mealworms. After helping prepare diets in the early afternoon, I faced the task of opening the shipment of boxes. Being slightly squeamish around bugs, I took a deep breath before taking out a pocketknife to separate the tapped boxes. Even though I’m not extremely grossed out by mealworms, I have never dealt with so many. But then again, I’ve never worked in a zoo commissary before. Each cardboard box housed about 1000 mealworms, which needed to be transferred to the large plastic mealworm tub in the commissary. The crickets proved to be a bit trickier. I had to make sure they did not escape while I relocated them into the two large cricket garbage cans.

Lemur lunch contains a variety of chopped up fruit. This particular day's lunch includes berries, cantaloupe and peaches.

String 7 prepares most of its diets in the Children’s Zoo kitchen, so most days the other intern and I get to chop up and measure produce for the lemurs, pigs and rabbits. Typically, I bring a reusable bag down to the walk-in commissary refrigerator to go “grocery shopping.” A plethora of fruits, vegetables and leafy greens fill the shelves and plastic cartons. The lemurs’ lunch is one of the most enjoyable to prepare because it usually consists of fresh fruits like cantaloupe, bananas, blueberries or peaches. The zoo keepers try to have a lot of variety in their diet, which also depends on the produce donated to the zoo.

I chop and measure out leafy greens and fresh produce for String 7's rabbits.

While going “grocery shopping” in the commissary, I began to learn the names of leafy greens included in the diets and learn the animals’ preferences. Sure, I was already familiar with Romaine lettuce, spinach and bok choy. But after the first few days, I began to identify the rainbow Swiss chard, collard greens and jicama. Just as not all people are avid vegetable eaters, the lemurs are not as fond of their daily greens. Consequently, we feed them most of their vegetables for dinner so they have more time to eat them before breakfast the next morning.